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(11) | EP 0 174 099 A3 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Fiber optic terminal interface |
| (57) The present invention is a communications link between a data processing apparatus
and a user input/output terminal. In the data processing apparatus (120) a data transmitter
multiplexes monochrone digital video data (211) with Manchester encoded ancillary
data such as keyboard control data (212) and sound synthesis data (213) for tranmission
via a first communications link (122). The Manchester encoded data has a clock rate
tied to the video dot rate of the digital video data and is transmitted during the
horizontal retrace interval. The receiver (230) in the terminal (130) uses the self
clocking nature of the Manchester encoded data for clock detection, demultiplexing
and synchronization. This receiver (230) then generates video data (231), keyboard
control data (232) and sound synthesis data (233) for utilization and a clock signal
(235) for controlling return data. A data transmitter (240) in the terminal (130)
receives keyboard input data (241), mouse input data (242) and speech input data (243)
for encoding in conjunction with the clock signal (235) and transmission to the data
processing apparatus (120) via a second communications link (126). A second receiver
(220) is connected to the second communications link (126) and generates demodulated
keyboard input data (221), mouse input data (222) and speech input data (223). In
the preferred embodiment the two communications links (122, 126) comprise optic fibers. |